Although most cases of PD are sporadic, 5 to 10% of cases develop at a much younger age, which are caused by mutations in one of several familial genes, including α-synuclein, PTEN-induced kinase 1 (PINK1), parkin, LRRK2, DJ-1, ATP13A2, and FBXO7 (6, 7). The gene discussed is PINK1; the disease is Parkinson disease.